I have the same issue on all our new W520 in the lab. Some of them have the 1000M GPU, other the 2000M. As soon as I switch to discrete graphics mode, I experience the issues described above. All works fine when switching to integrated graphics. But on the other hand, when I change brightness during boot-up, the system still freezes at least some times, so I am not sure if this is really GPU related at all...
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/776999 Title: [Lenovo W520] laptop freezes on ACPI-related actions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
